Topic: Olds 403 Build

[TheKid]

Don't worry about thread jacking. I want this thread to be as full of knowledge, no matter how off topic, about the 403 as possible. Thread jacking pertaining to a 403 build is completely acceptable and encouraged!

[joe d]

No it actually is about 1/2 and1/2, Kit is about $500 and labor $500.   Break it down any way you want it is a good deal!    Thing is I already had the head work done so just need the bottom half done now.  But I don't necessarily need new Pistons so maybe just a hone?   Sorry "Kid" Bad thread jacker! BAD!

that is amazing

[Wallington]

I'd be very worried about what you got for that, the quality of the parts, the quality of the labor, or care taken to put it together properly and set up. That amount wouldn't have even covered the first half of my machinework, boring out and preparing the basic block, ignore parts or labor, further machining to to match parts better. Actually it cost nearly that much to just swing the engine and trans in when done with a bit of playing around to get chev converter to fit properly, it doesn't take much to add up especially if an slight adjustment is needed, which might be ignored to save costs.

[joe d]

i am sure there is no boring involved or new pistons, but still 20 years ago i got $2k labor to rebuild a v8 plus machine work and parts, i am with you on this as i see no way a skilled engine builder can or would rebuild a short block for $1000 including parts

[72blackbird]

JJ,
Cams are another area where everyone has their opinion, and of course has their preference. Some like it lopey, some like it smooth w/ a hint that it isn't stock, etc. The general consensus is that you'll have to run at least an advertised duration of over 280 degrees, .480" lift, and around 226-230 degrees duration @.050 to make around 375-400 hp- this is provided your whole package is matched to use this cam. Cams with a tighter lobe separation angle, like the 110 LSA Comp cams, work slightly different- because they tend to make power sooner their power curve also tends to drop off at higher rpms as opposed to 112-114 LSA cams. In any case, consult your builder and ask what he recommends with the parts you are running.

I typically only pull the engine alone, since I usually am only working on that and don't need the extra work of dealing with the larger mass of an engine/ trans assembly, as well as having to find a place for a trans in my crowded garage. I will only pull both engine and trans if the trans is a stick- much easier to install a clutch and pressure plate with the engine on the floor out in the open. The heads on an engine have enough bolt holes on the front and back for you to attach a chain to it- should be a straighforward operation if you take care and make sure everything is unbolted from the engine.

Geno

[TheKid]

Geno,
I'm going to keep a build going on RealOldsPower too to help gather good info. I know I want a lopy idle, I really like that feel and sound. I want to pick the right cam the first time, to maximize the fun of this motor. I do want over 400hp, not by much, but just a little, and lots and lots of torque. I'll just need to research. I have an idea of the other pieces I'd like to use as far as intake etc goes, but would it be a better idea to pick a cam with the duration and lift I like, and build the motor around the cam?

JJ

[72blackbird]

JJ,
I don't see why a Comp Cams XE 274 wouldn't work well in a 403- it does well in 9.5:1 400's so I would estimate the idle and performance to be similar, if both engines had the same carb, exhaust, gearing, torque converter, etc. Of course the induction and ignition would have to be tuned specifically to your setup, but it would be close to a 400 with similar compression and gearing.

Geno

[oldskoolubr]

The only thing I would Advise is the Olds lifts on the same cams tend to be higher(Pont. .488/.491 Olds .520/.523) so might need different springs.  The XE268 would probably be more closely suited to that motor(Disclaimer IMO)  

[TheKid]

Does the XE268 get me closeish to the powerband/hp tq I'd like to have? I'm still pretty new to looking for cams for these motors...used to build BMW's ha.  I got the motor out today!!

[Wallington]

The only thing I would Advise is the Olds lifts on the same cams tend to be higher(Pont. .488/.491 Olds .520/.523)

That's the different ratios of Pontiac being 1.5 and Olds being 1.6 but still similar in relative terms, which isn't easy to compare as different engines, just the specs. It all depends on the rest on the combination.

[oldskoolubr]

Ohh Ok, I was wondering?  Well he said he was doing the roller rockers?  Makes sense now!  Same principles still apply right?!

[TheKid]

Yes, I do want to go with roller rockers, don't know how to adjust the setup properly, but I 'll learn! This is all supposed to be one big learning experience! It's been great so far. I'm still working on piecing the right parts for the motor as far as cam/roller setup/intake.

[72blackbird]

JJ,
Mondello Performance is the one-stop shop for Olds performance engine parts- they have what you need, as well as the parts to make a 403 block more reliable.

http://www.mondellotwister.com/PartsIndex.htm

Geno

[oldskoolubr]

Mondello isn't the recommended "Olds" one stop shop like it used to be?!  Most their stuff is Isky if I am not mistaken and costs less if you just buy Isky!  Talk to CutlassEfi over on RealOldspower he can custom grind something for you or at least point you in the right direction!  Lotsa good info out there just determine what is your main goal: Torque, Hp Topend Etc and tailor the cam to that and your Build!   I am in no way discounting what Geno has told you just what I have learned researching my build and Mondello's has dropped off considerably over the years!   Another possibility is Terry at FCR but I have heard mixed reviews on their order reliability!

[Wallington]

If you know what you need and have shopped around then Mondellos are probably fine, but yes, it's only the name for trading now and not the reputation it once had.

Yup, CutlassEFI (Mark) did my custom camshaft. Very helpful guy and easy to deal with and was prepared to go through and explain different setups and results long before I mentioned the possibility of buying a camshaft. Others don't want to know you unless you are sending them money, or provide further information or feedback long after you have fitted it up.

Not sure if Terry is even around anymore as such. He disappeared off the groups and became hard to track down a few years back when his Wife passed away and never really returned that I've seen, which is a shame as he also seemed to be very helpful and full of information before then, and produce specialist items that no one else has done for Olds since.